Black Holes

[Shrek]

Yep, and there is an interesting story to go with that:

Physicists and Engineers worked on the GPS project, but came to a disagreement. The Engineers saw more than one gravitational time dilation effect and the Physicists said it was one and the same effect seen in two different ways and so should not be doubled; each refused to launch with the others claim.
The clever management solution was to have a switch in the software so it could be run either way, and they launched.

Turned out the Physicists had mastered their art, but I have sympathy for the Engineers; I happen to be both a Physicist and Engineer so really like this story which I seem to recall reading in the book Exploring Black Holes: Introduction to General Relativity by Taylor and Wheeler. The second edition is free (Exploring Black Holes: Introduction to General Relativity, Second Edition : John Archibald Wheeler, Edwin F. Taylor, Edmund Bertschinger : Free Download, Borrow, and Streaming : Internet Archive), and I see the story is still there (Chapter 4, section 10)

This is not a pirated copy as the authors chose to give it away free.

 

[qubit]

There is a proposal that time stops at the Horizon and does NOT start up again below, i.e. it is only space inside a black hole.

(PDF) Cosmic censorship and the evaporating Black Hole (researchgate.net)
equation 15

Disclosure: I happen to be first author

It's not a proposal, it happens. General Relativity shows that time does stop at the horizon compared to a far away observer. Hence, an object falling in get extreme red shifted and fades from view. We never see it cross the horizon.

The speed of light is the maximum speed of causality.

 

[Shrek]

It is the second part I was questioning

Most people have time starting up again below the Horizon

 

[qubit]

It is the second part I was questioning

Most people have time starting up again below the Horizon

Ok, fair point.

I've seen explanations that there is, or could be, an inner horizon too and I have no idea how that works. I think its existence or otherwise may be related to spin and / or size, can't remember now.

 

[Shrek]

There is for the spinning (Kerr) black hole; but I stuck with the non-spinning (Schwarzschild) black-hole as the added complexity was a distraction.

 

[lexluthermiester]

How do I think beyond this plane? -X, +X, -Y, +Y

You mean X/Y/Z/T?

A black hole is just the extreme case where time has come to a relative halt at the Horizon.

Except that time can not stop. It can be decelerated, but not halted. This is part of where General & Special Relativity fails, because it can not predict what happens to matter when it falls into a Black Hole object.

 

[Space Lynx]

You mean X/Y/Z/T?

no I was thinking of two dimensional thinking as being a limit (aka the blanket / taught example), I thought that is an expression of 2d? perhaps I am wrong, I am not so good at math.

 

[lexluthermiester]

no I was thinking of two dimensional thinking as being a limit (aka the blanket / taught example), I thought that is an expression of 2d? perhaps I am wrong, I am not so good at math.

Even 2 dimentional states are governed by time, so in reality 2 dimensional states are not possible. Likewise neither are 3.

Ok, gonna dig in here.

I have been thinking of the way gravity works

You're brave. Not many try. So here we go.

what if black holes are actually the good guys of the universe? and without their might and power sucking, the acceleration would actually be faster?

The effect Black Holes have on the expansion of the Universe as a whole is so small as to be insignificant. The forces driving the expansion are so immense that gravity has almost zero influence.

the acceleration of galaxies moving away from each other I mean - sort of like the Big Crunch, but instead with a SNAP what if gravity is like a like layer - and as the universe that we can see continues to expand - gravity "stretches" so that image above, the curve will be less and less over time - but black holes being so immense (since almost every galaxy requires a giant one at the center to become a galaxy) act as the ultimate form of gravity, insanely hungry and dense - preventing this SNAP

This is a concept that many have touched on, but is not possible. The expansion of the Universe is not "stretching" anything. The outward expansion shell of the Universe is simply pushing through space that already exists, it is not creating new space. If we were "stretching" we would be completely unaware of it and would not be able to observe it because we would be stretched in equal proportions and thus giving the observable effect of not expanding at all. So the fact that we can observe the expansion of the Universe on any scale at all proves that we are not being stretched. It also lends very strongly to the idea that the Big Bang took place and the Universe is an outwardly expanding object. Simple deduction, sure, but that conclusion requires an understanding of the grand cosmological scope.

I am sure someone like her though would instantly look at it and be like oh you are way off and here is why

Kinda like what I just did? LOL!

Black Holes are natures great recycling bin. Stuff goes in and then, after a very long time(measured in trillions of trillions of years), is expelled after certain conditions are met. The Big Bang of our Universe is not the first, nor will it be the last.

 

[lemonadesoda]

I think I'll get my coat...

 

[Shrek]

The forces driving the expansion are so immense that gravity has almost zero influence.

Little confused; what forces?

If I throw a ball up, no forces act (except gravity) once it has left my hand.

If you talk of dark energy, then the Cosmological constant is a candidate.

 

[InVasMani]

It's time for your cosmological scope checkup Lex. That's a different kind of expanding universe.

 

[lexluthermiester]

Little confused; what forces?

Momentum for a start.

If I throw a ball up, no forces act (except gravity) once it has left my hand.

Could you restate that?

If you talk of dark energy, then the Cosmological constant is a candidate.

No, I'm not talking about dark energy.

It's time for your cosmological scope checkup Lex. That's a different kind of expanding universe.

How so?

 

[Shrek]

Momentum for a start.

Could you restate that?

No, I'm not talking about dark energy.

Momentum is not a force

Gravity would be slowing down the expansion (if it were not for dark energy)

 

[lexluthermiester]

Momentum is not a force

Don't split hairs. You know what I'm talking about. The amount of mass observed moving and accelerating can not and will never be effected by gravity to any degree that will be significant, otherwise the Universe would be slowing down and would eventually collapse back into a Black Hole. This is not what we are observing when we look out into space.

Gravity would be slowing down the expansion (if it were not for dark energy)

Incorrect. There is far more mass to be decelerated than gravity has the ability to effect.

 

[Shrek]

Gravity comes from the mass... but I'll defer to you

I'm out

 

[lexluthermiester]

Gravity comes from the mass...

Of course. But the momentum of the mass is greater than that which gravity can overcome or even greatly effect. Additionally, as the mass of the Universe continues to spread out, the influence of Gravity lessens and the acceleration of the Universe continues to increase.

 

[Space Lynx]

black hole expert Dr. Becky: I finally got around to watching this day in the life video of what its like to be a black hole expert... honestly kind of glad I didn't major in this stuff, the sheer amount of hours in this video where she is just looking at data sets and command prompts would melt my eyes... I have a lot more respect for astrophysicists like her now. not that I didn't before, but that is just really draining work imo

 

[the54thvoid]

^^ This is sort of what I'm trying to allude to when I talk about this field of science. An incredible amount of work goes into data crunching, and it's all numbers. We, the casual end-user, want a pretty picture and a convenient factoid to feel content with. Then people say things like, 'I feel that it's blah, blah, blah.' But feelings and inferences from a one -hour show can't convey the sheer weight of mathematical and observational science that goes on. This isn't a dig at you Lynx, just a generalisation.

Science is about observing (a possible theory), calculating (the significance of results), and validating or rejecting. There are no feelings in science. That's what philosophy is for: to ramble about existential thoughts and posit some flowery explanation for why 'x' is 'not y'.

 

[Space Lynx]

^^ This is sort of what I'm trying to allude to when I talk about this field of science. An incredible amount of work goes into data crunching, and it's all numbers. We, the casual end-user, want a pretty picture and a convenient factoid to feel content with. Then people say things like, 'I feel that it's blah, blah, blah.' But feelings and inferences from a one -hour show can't convey the sheer weight of mathematical and observational science that goes on. This isn't a dig at you Lynx, just a generalisation.

Science is about observing (a possible theory), calculating (the significance of results), and validating or rejecting. There are no feelings in science. That's what philosophy is for: to ramble about existential thoughts and posit some flowery explanation for why 'x' is 'not y'.

As someone who loves ancient philosophy, I have to disagree with your depiction of what philosophy is, but the rest of it I agree with.

 

[lexluthermiester]

black hole expert Dr. Becky: I finally got around to watching this day in the life video of what its like to be a black hole expert... honestly kind of glad I didn't major in this stuff, the sheer amount of hours in this video where she is just looking at data sets and command prompts would melt my eyes... I have a lot more respect for astrophysicists like her now. not that I didn't before, but that is just really draining work imo

It's not just an Astrophysics thing...

 

[Space Lynx]

It's not just an Astrophysics thing...

I know, coders, etc have that life too. She mentions how you have to learn Python and other languages in the video.

 

[lexluthermiester]

I know, coders, etc have that life too. She mentions how you have to learn Python and other languages in the video.

Yeah. That's actually a roadblock for some people.

 

[Space Lynx]

Yeah. That's actually a roadblock for some people.

I tried a few years ago. I just can't do it, hurts my eyes after 20 minutes.

 

[lexluthermiester]

I tried a few years ago. I just can't do it, hurts my eyes after 20 minutes.

You're not alone. This is why Scientists need assistants and research teams with varying skills. Those team members fill in the skills gaps the lead doesn't have.

 

[Frontino]

I was thinking if beyond the event horizon gravity slows time almost to a still, then temperature should be about absolute zero, because atoms movement also basically stops, don't you think?